This invention is concerned with cooling downhole electric pump motors and associated apparatus in high temperature environments.
It has been conventional practice to employ ambient-temperature well fluid as a medium for dissipating the heat generated by the electric motors of submergible pumps. In wells with ambient downhole temperatures of up to about 250.degree. F., this technique has been satisfactory. With substantially higher downhole temperatures, e.g. 300.degree. F.-500.degree. F., as may be encountered in geothermal wells, the well fluid is too hot to serve as the required heat dissipation medium, and the insulation, lubricant, and bearing materials of commercially available pump assemblies suffer from the effects of high temperature. It has, of course, been known to circulate coolants through electric motors, but such techniques have certain complexities, including, usually, the need for specialized motor or heat exchanger structures.